Impeller for rotary pumps



E. c. KIEKHAEFER 2,466,440

IMPELLER FOR ROTARY PUMPS Filed July 29, 1948 E M w, w e FW 2 J, 4 m 5 m 11m fl 9% W K a @X. 4 UM A f a 4 f a pril 5, 1949.

Patented Apr. 5, 1949 UNITED STATES PATENT OFFICE 2,466,440 IMPELLER. FOR ROTARY PUMPS Elmer Carl Kickhaefer, Cedarburg, Wis.

Application July 29, 1948, Serial No. 41,262

6 Claims.

This invention relates to impellers for rotary water pumps and the like particularly adapted for use in cooling systems of outboard motors.

A principal object of the invention is to provide for the longer life and service under adverse conditions of plastic-or rubber impellers and reduce the possibility of their structural failure and consequent damage of the motor.

A more particular object is to provide for the improved flexing characteristics of impellers of molded plastic, rubber or the like having vanes formed integrally with the base thereof and which will maintain a greater resiliency and eflioiency with long periods of use or disuse.

Another object is to provide for the bonding or securing. of an impeller of rubber or plastic to a metallic hub insert therefor which will not become loose after an indeterminate period of service.

Another object is to more effectively seal the area between the impeller and the pump casing without reducing the efficiency of the pump.

A further object is to provide a seal which will allow foreign particles to pass between the impeller and pump casing walls without damage to the same.

Another object is to provide a larger bonding area between the metallic hub and the rubber or plastic rotary pump impeller.

A further object is'to provide an improved bonding of a rubber or plastic rotary pump impeller to a metallic hub wherein a substantial portion of the bond is subjected only to shearing stresses in service and will therefore be less subject to tearing and failure.

Another object is to provide limited emergency service of rubber or plastic impellers for rotary pumps bonded to metallic supporting means notwithstanding a partial or complete breakdown of the bond.

These and other objects and advantages will be more fully set forth in the following description of a preferred embodiment of the invention as illustrated in the accompanying drawings.

In the drawings:

Figure 1 is an axial sectional view of a rotary pump with the impeller in elevation;

Fig. 2 is a'transverse sectional view of the pump taken on line 22 of Fig. 1;

Fig. 3 is an enlarged view of the impeller with a portion broken away to show the metallic hub insert therefor;

Fig. 4 is an enlarged section of one vane of the impeller taken on line 44 of Fig. 3; and

Fig. 5 is a view showing the flexing stre ses 1 of one vane of the impeller of the present invention. 1

The pump for use with the invention comprises the outer casing I having opposite end walls 2 and 3 secured to the casing to close the pump chamber 4.

The pump impeller shaft 5 is rotatably mounted and extends through end walls 2 and 3 and may be provided with packing seals, not shown, to prevent leakage.

The impeller 6 mounted on shaft 5 within chamber 4 comprises the main body portion 1 and a plurality of deflectable radially extending vanes 8 formed integrally with body 1. Shaft 5 and impeller 6 are eccentric to the cylindrical wall 9 of chamber 4 to provide for the flexing of the vanes and the operation of the pump with rotation of shaft 5. I

Contact of the tips of the vanes 'and wall 9 is maintained by the resiliency of the vanes which are flexed with each revolution of the shaft 5.

Vanes 8 fit within chamber 4 to contact the two sides of the chamber and the peripheral outer wall thereof. The v-shaped feather edges I0 along each edge of vanes 8 and the concentric feather edges II on each side of the body 1 of the impeller contact the end walls of the pump chamber 4 to provide a seal thcrebetween.

The inlet and outlet ports l2 and' I3, respectively, open into chamber 4. The liquid to be pumped enters into the pump chamber through port l2 and is discharged through port I3 under pressure by the rotation of impeller 6 in one.

direction, and vice versa by the rotation of impeller 6 in the opposite direction.

Each vane 8, as shown in the drawings, is thin at the tip and increases to a substantially larger section at the base thereof joining body 1 so that in operation the flexure of the vanes is distributed evenly by movement thereof throughout the length of the vanes and their tendency to break down or tear from the body portion 1 of the impeller is reduced.

As the vanes move rotationally the area of greatest flexing moves from near the tip at the intake side of the pump to near the root of the vanes at the discharge side of the pump as shown in Fig. 1. The unit cross-sectional stress is substantially the same throughout the length of the vane in accordance with the loading principle of a cantilever beam fixed at one end.

The bushing or hub [4 for carrying impeller 6 by shaft 5 comprises a metallic sleeve insert bonded to the impeller by means of a suitable bonding agent, not shown, therebetwee'n with body 1 of the impeller preferably overhanging each end of the hub, as shown in the drawings.

The gear teeth IS on the outer circumference of hub I4 are embedded in the ,body of the impeller in the forming thereof. Hub I4 is secured to shaft 5 for rotation by means of the key It.

In the ordinary sleeve bushing the flexing action of the vanes tends to pull sections of the impeller body radially outwardly and tear the bond between the impeller and the bushing.

In the present invention the bonding area between hub I4 and impeller 6 is greatly increased and in the operation of the pump a substantial portion of the bonding area is subjected by flexing of the vanes only to shearing stresses in the direction of arrow I! which the bond is most adapted to withstand.

In this manner the tendency of the vanes'to tear the bond securing the hub and the impeller is substantially reduced, affording additional strength and allowing the use of vanes 8 having the larger, reinforced base sections, as described above. The improved bond thereby permits the root of the vanes to be increased correspondingly in size for increased serviceability and efficiency as described.

The gear teeth I! embedded in the impeller will carry the impeller for a short period of time thereby affording a limited period of emergency service in the event the bond does break.

The feather edges provide an efficient seal between the impeller and pump casing without materially increasing the drag of the impeller on the shaft and the bond securing the impeller to the hub and permit the vanes to flex without binding between the end walls of the casing.

Foreign particles entering the pump are easily passed by the vanes until discharged with the pumped fluid without injury to the impeller.

Various embodiments of the invention may be employed within the scope of the accompanying claims.

I claim:

1. An impeller for a rotary vane-type positive displacement pump having a pump drive shaft, comprising a metallic hub for mounting on the pump drive shaft to rotate therewith and having a plurality of radially extending teeth on the outer circumference thereof, an outer body of resilient flexible material molded over the circumference of said hub and bonded thereto.

throughout the coextensive surfaces thereof, said hub extending short of the end faces of said body and being embedded in said body with the ends of the body extending inwardly over the ends of said hub to provide a bond therebetween at each end face of the hub extending substantially continuously throughout the circumference, and a plurality of radially extending vanes of generally tapered thickness formed integrally with said outer body and having a thin tip and a thicker root section for each vane whereby the flexing of the vanes in service is maximum at the tips thereof, the bonding of said teeth and said ends of the body and hub providing substantially radially extending shear areas to resist breaking of the bond between the hub and outer body by generally radial stresses in the outer body arising from flexing of the several vanes as the impeller rotates.

2. In an impeller for rotary pumps of the class described, a central molded tubular body and a plurality of radially extending flexible vanes molded integrally therewith of a resilient flexible material and adapted to rotate in a pump chamber under conditons of substantially high stress in the body from flexing of the vanes, and a metal insert liner for the body which is adapted to be secured .to a pufnp shaft for rotating the impeller with the body bonded continuously to the outer circumference of the liner throughout the coextensive surfaces thereof, said impeller body being molded upon said liner with the ends of the body of the impeller extending radially inwardly over the ends of the liner and bonded to said liner ends substantially continuously throughout the circumference thereof, whereby the generally radial stresses in said body resulting from the severe flexing of the several vanes during rotation are resisted by end bond areas in shear and the outer circumferential bond between the body and liner is protected against rupture.

3. In a rotary vane-type positive displacement pump of the class described, a pump housing providing a pump chamber with inlet and outlet ports and having circumferential walls and end walls adapted to confine an impeller therein, a shaft extending through at least one of said end walls and disposed eccentrically to said circumferential walls, and an impeller of generally larger diameter than said circumferential walls and having a molded impeller body mounted on said shaft within the pump housing and sealed against said end walls, a plurality of radially extending flexible vanes of tapered thickness formed integrally with said body of resilient flexible material, and compressibie ridges extendingalong the sides of said ,vanes facing said end walls and formed integrally with the vanes to engage the end walls of the pump housing and provide a seal between the vanes and end walls free from binding and which prevents the entrapment of foreign material between the vanes and the end walls at all times during flexing of the vanes and rotation of the impeller.

4. In a rotary vane-type positive displacement pump of the class described, a pump housing providing a pump chamber with inlet and outlet ports and having circumferential walls and end walls adapted to confine an impeller therein, a shaft extending through at least one of said end walls and disposed eccentrically to said circumferential walls, and an impeller of generally larger diameter than said circumferential walls and having a molded impeller body mounted on said shaft within the pump housing and sealed against said end walls, a plurality of radially extending flexible vanes of tapered thickness increasing in cross section from the tips to the roots thereof formed integrally with said body of resilient flexible material, and a V-shaped ridge extending substantially centrally along the sides of each vane facing the corresponding end walls of the pump housing, whereby said ridges provide a seal between the vanes and end walls free from binding and which passes foreign material without entrapment of the material during flexing of the vanes and rotation of the impeller,

5. In a rotary vane-type positive displacement pump of the class described, a molded impeller having a central tubular body portion and a plurality of radially extending flexible vanes integral therewith and of a resilient flexible material, and a pump housing providing a pump chamber with inlet and outlet ports and having circumferential walls generally of a smaller diameter than said impeller and disposed eccentrically relative thereto and end Walls sealed in direct pressure engagement with said impeller, the flexible vanes of said impeller having a relief extending along the side edges of the vanes facing said end walls to present an area of pressure contact for the vanes with the end walls substantially narrower than the thickness of the vanes and extending from the central body portion of the impeller to the tip of each vane, whereby the vanes are free to flex without binding against the end walls and a seal is provided which prevents entrapment of foreign material between the vanes and the end walls.

6. In a rotary vane-type positive displacement pump of the class described, a molded impeller having a central tubular body portion and a plurality of radially extending flexible vanes integral therewith and of a resilient flexible material, and a pump housing providing a pump chamber with inlet and outlet ports and having circumferential walls generally of a smaller diameter than said impeller and disposed eccentrically relative thereto and end walls sealed in direct pressure engagement with said impeller, the flexible vanes of said impeller being constructed with a thin projecting area of contact extending along each side edge of the respective vanes facing the corresponding end walls of the pump from the tip to the root of the vanes and of a width substantially less than the thickness of the vanes, whereby the narrow projecting contact areas of the vanes are compressibly sealed against the corresponding end walls and the vanes are free to flex under the influence of said circumferential walls and rotation of the impeller Without binding against the end walls and foreign material is prevented from becoming lodged between the vanes and the end walls.

E. CARL KIEKHAEFER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,004,712 Thiry 1 June 11, 1935 2,070,738 Klein Feb. 16, 1937 2,246,488 Fraser June 17, 1941 2,272,900 Saurer Feb. 10, 1942 2,293,268 Quiroz Aug. 18, 1942 2,297,619 Haberstump Sept. 29, 1942 1 2,460,617 Balogh Feb. 1, 1949 2,460,952 Simer et al Feb. 8, 1949 FOREIGN PATENTS Number Country Date 9,771 Great Britain 1908 344,118 Great Britain Mar.'5, 1931 464,475 Great Britain Apr, 16, 1937 736,262 France Sept. 13, 1932 

